1. Technical Field
Several aspects of the present invention relate to a biological information acquisition device, a method for acquiring biological information, and a biometrics device that utilize biological information.
2. Related Art
Recently, in order to authenticate an authorized user, biometrics has been introduced that utilizes the user's biological information such as fingerprints, irises, and vein patterns. For example, it is cited in Japanese Patent No. 3549795. For implementing the biometrics, various biological information acquisition devices are used.
Among the devices, one is known that is provided with a light source for light irradiation and a light receiving element for receiving light. The device irradiates a biological body with light from the light source and receives light from the biological body to convert it into an electrical signal, acquiring biological information.
In these days in which apparatuses, such as portable devices and personal computers, that need authentication are widely used in daily life, biological information acquisition devices with a large body and high power consumption are given the cold shoulder by users.
In contrast, improving the accuracy of acquired biological information is demanded since higher accuracy is required in authentication by increasing security awareness.
However, a problem arises in that the quality and accuracy of the acquired biological information get lowered since the dynamic range of irradiation light and received light is limited. Particularly, light sources and light receiving elements used in small biological information acquisition devices are strictly limited in their power consumption, driving method, and size, which makes it difficult to use ones having high performance in terms of the dynamic range or the like.